Running OS 9 on unsupported (newer) Macs

[Mike Richardson]

Has anyone really sat down and tried to run OS 9 on newer, unsupported Macs?

For example - the FW800 MDD G4s.

There's some iMac G4s that use regular AirPort, USB 1.1, etc. but can't boot OS 9. I remember reading a report that said you could take the ROM file off of some service disc and then it would boot OS 9, and everything pretty much worked. The main problem is acquiring such "service discs".

Some eMacs shipped with AirPort Extreme and could boot OS 9 (these were sold primarily to Education customers) except AirPort would not work. You had to use the OS 9 discs that came with the eMac. These discs might also have a newer ROM that could possibly boot the iMac G4.

I'm not talking about anything with a G5 or newer. They are just too different.

 

[Byrd]

If there is no Classic OS ROM available (or written for a particular Mac model) I don't think much is going to happen.

The FW800 MDDs are peculiar beasts in that the later 2003 FW400 models did work with OS 9. I'm guessing that the FW800 are different beasts indeed, perhaps close to the single 1.6Ghz G5 tower in terms of components used.

JB

 

[protocol7]

From what I've seen online you need a Mac OS ROM version 9.5.1 or higher to boot the MDDs. Some people also had success booting the first classic-only iMacs using a 9.8.1 ROM that Apple used on a specific MacTest Pro disc (MacTest Pro for Power Mac G4 (March 2003) Version 7.8.1). My late 2002 iBook came with 9.7.1 on the Classic image. Also, if you grab "Netboot for OS 9" from Apple, you can extract 9.2.2 images (Applications and System Folders) from it (using Pacifist) in English, French, German and Japanese that have ROM 9.6.1.

In theory if you either install 9.2.2 via OS X or TDM and then replace the ROM file, it should work. I'm guessing the later the ROM the better, as they should all contain the extra boot and other fixes that the previous versions had, but I can't say that for sure as I don't have any of the "right" machines to test this on. The latest ROM revision I could find mention of online was 10.2.1.

 

[Mike Richardson]

ROM 10.2.1 shipped with Power Mac G5s for use in the Classic Environment. I don't know if it's any better than the rare ROM 9.8.1 (which is not available online anywhere). It might actually be worse.

I have a 1 GHz iMac G4 I could test with actually.

 

[ccmac]

For booting OS 9 on a FW800 G4, see my discussion in this thread: http://68kmla.org/forums/viewtopic.php?f=3&t=9967&start=0

Regarding ROM 10.2.1, I have seen it suggested that it contains MDD bug fixes for booting into OS9.

The special 9.8.1 rom that came on a MacTest Pro disc that supposedly allows OSX only macs to boot into OS9 is somewhat of a myth. It only supports OS9 booting on one single OSX only model, the iMac (Flat Panel) 15 inch (and that model did in fact previously support OS9 booting). Those who have tried the 9.8.1 rom on other OSX only G4s have discovered it does not allow them to boot into OS9. However, there was also a special blessed system file called "Custer" on that MacTest Pro CD and I haven't seen anyone do much with this file to see exactly what it does.

There was also a French company that developed a firmware patch called Countdown G5 that allowed OS9 booting on G5s. See http://db.tidbits.com/article/7617.

 

[protocol7]

For booting OS 9 on a FW800 G4, see my discussion in this thread: http://68kmla.org/forums/viewtopic.php?f=3&t=9967&start=0

I found the Japanese article you linked there before. His second method looked interesting. It seems that the ROM header contains the list of compatible machines. Normally it just contains MacRISC, but the 9.8.1 ROM lists MacRISC, PowerMac4,2 and PowerBook4,3 (which would explain the extra supported machines). I guess he's saying that editing it to MacRISC3 would add support to similar machines.

 

[Mike Richardson]

There was also a French company that developed a firmware patch called Countdown G5 that allowed OS9 booting on G5s. See http://db.tidbits.com/article/7617.

That's an April Fools joke xx(

 

[Mike Richardson]

Just for fun, I'm trying a few different Open Firmware commands to see if I can get my G5 to even attempt to boot OS 9.

I have Mac OS ROM 10.2.1 and 9.8.1 at my disposal. I modified the Mac OS ROM 10.2.1 to include "MacRISC3" and "MacRISC4". I'm not sure if I also need to add "PowerMac7,3" or not.

I have to use Open Firmware to set the boot variables. Obviously I cannot select OS 9 in the Startup Disk control panel.

So far, it will sit at a black screen for several seconds, load a grey screen (maybe OS 9 just starting to load?), then flash to another grey screen with the missing system folder icon, then it will boot to Tiger that I have on a backup drive.

Upon further inspection of ROM 9.8.1 they have PowerMac4,3 listed so I guess I should try listing PowerMac7,3 in either ROM.

Interesting information: Right after I added MacRISC3 to the ROM 10.2.1 and saved it in HexEdit, the G5 hard froze. Coincidence???

 

[Mike Richardson]

I had a theory that OS 9 would not understand the G5's SATA bus, but it might understand the regular IDE bus (normally used for optical drive).

However moving everything to the IDE bus did not deliver any greater results.

I wonder what ATA chip the G5 has. It is LBA 48-bit (despite the fact that it's only used for optical drives - it works fine with large IDE hard drives as well, you can even use Master/Slave if you can mount the extra drive somewhere and split the power rail). Equill said that only ROM 10.2.1 (which I have been using) will support LBA 48-bit.

It really seems like it just starts trying to load OS 9, but OS 9 gets massively confused and aborts all the way to the blinking system folder icon, where Open Firmware takes over again and tries to locate a suitable replacement System to boot from.

I think the G5 processor or bus or something is just too crazy different for this to ever work. However I think there could be success with G4 models that dropped OS 9, such as later eMacs, iMac G4s, PowerBook G4s, and maybe even iBook G4 or Mac Mini G4. I think these are all close enough, and often they didn't change much in terms of chipset. For example, TAS3004 was used on almost every Mac from the era and I'm sure at least one of those booted OS 9 natively, therefore OS 9 supports TAS3004 sound.

Biggest problem I see is USB going dead due to the lack of USB 2.0 drivers, which means no keyboard or mouse. This could be resolved on the MDD G4 with a PCI card. Also PowerBook G4s and iBook G4s still used ADB internally for their keyboard and trackpad so those would still work. (Hack idea: turn internal trackpad connection into external ADB port)

 

[equill]

Support of OS 9 by G4 MDDs has already been treated here, most discursively in

viewtopic.php?f=3&t=9967&p=99383

both as to the Classic Environment components and 48-bit LBA enablement under OS 9. The two Install and restore DVDs released with the M9145 1.25GHz MDD that could again boot into OS 9.2.2 postdate the withdrawal of the FW800s. For example, the Install Applications and Mac OS 9.pkg alias is dated 25 Jan. 2004. I suspect that whatever prevented FW800s from booting into OS 9 lay elsewhere than in the system software, however simple it may be for the energetic or the determined to circumvent it.

It needs to be taken into account that 48-bit LBA-savvy OS 9 installations can still choke on HDDs of more than 190GB (unless a FireWire bus is used) and more than 1.5GB of RAM.

de

 

[ccmac]

Another thing that is easy to forget is that you need to make sure the hard drive has the OS 9 drivers installed. If you try to format a hard drive on a OSX only mac such as the FW800 MDD, the option to install the OS 9 driver has been removed. Use a drive pulled from a OS9 bootable G4.

 

[Mike Richardson]

You are right. I totally forgot about this. I don't think either drive I tried has the OS 9 drivers.

 

[Mike Richardson]

I put my G4's hard drive in the optical drive bay.

The video card stops working!

I take it out.

The video card works again!

Brilliant.

The only reason I can think of is that they both share a split power rail (the video card requires extra power), and this old 20 GB hard drive sucks up too much juice and knocks out the video card.

 

[Mike Richardson]

Another thing that is easy to forget is that you need to make sure the hard drive has the OS 9 drivers installed. If you try to format a hard drive on a OSX only mac such as the FW800 MDD, the option to install the OS 9 driver has been removed. Use a drive pulled from a OS9 bootable G4.

You are right. I totally forgot about this. I don't think either drive I tried has the OS 9 drivers.

This is interesting - I just connected a new FW800 hard drive to my G5, and Disk Utility offers the option to install Mac OS 9 drivers when formatting.

The drive is an Iomega eGo 320 GB, it's a laptop sized drive that works off FireWire power (or 2 x USB port power) with FW400, FW800, and USB ports. It comes already formatted as HFS+ with the OS 9 drivers. I personally recommend this drive to anyone who's looking for one, it's $79 at Fry's right now.

I'm going to reconnect the drive using FW400 (since OS 9 didn't have FW800) and try booting off of it.

 

[Mike Richardson]

This is a cropped picture of my G5 displaying a Mac OS 9 boot volume as a valid choice when holding down Option and booting the Mac.

Clicking on the OS 9 volume and then the arrow button causes the G5 to read a file from the external hard disk (probably the Mac OS ROM file), and then draw a grey screen for a split second before returning to the screen where you select a boot volume.

It would appear that a number of technical requirements can be met to set up the potential to boot Mac OS 9 on a G5. We can reach a point where the Mac OS ROM file is read into memory and execution of the file is started.

In an OS X booting situation, a file named "BootX" is loaded. This file is the same format as Mac OS ROM but contains only the minimum amount of code to bootstrap OS X. BootX contains the grey Apple, just as Mac OS ROM contains the Happy Mac.

Unfortunately, we don't get to the point of where we see the Happy Mac - or perhaps it is drawn so quickly and then removed due to some other problem.

I have not tried any of this on the MDD FW800 G4 yet but I plan to very soon. Progress on the MDD may lead to progress, or at least further explanation on the G5. Actual booting is probably impossible, but perhaps some interesting information can be learned.

 

[chet david]

I am interested in seeing this idea further pursued.

 

[trag]

I am interested in seeing this idea further pursued.

Mike Richardson seems to have been the primary driver of this effort and since he is no longer on these forums, we're unlikely to see any further progress reports.

I think he may be active on ppcmla though.

I too would like to see progress, but not enough to work on it myself. It would be super cool if the G4 Mac Mini could boot OS 9.

 

[ccmac]

There is a new discussion on the Low End Mac OS9 Group where someone has claimed to have discovered how to boot OS9 on a MDD FW800:

http://groups.google.com/group/macos9/browse_thread/thread/a262eca398f57645